Western Digital Technologies, Inc.

Sandisk Technologies Inc.

Philip David Reusswig

Nian Niles Yang

Grishma Shah

Sahil Sharma

Deepak Raghu

Rohit Sehgal

Pao-Ling Koh

Chris Nga Yee Yip

Alexander Bazarsky

Ariel Navon

Harish Reddy Singidi

Dana Lee

Zhenlei Shen

Chris Avila

Gautam Ashok Dusija

Karin Inbar

Anubhav Khandelwal

Idan Goldenberg

Rami Rom

Preeti Yadav

Prasanna Desai Sudhir Rao

Smita Aggarwal

Roi Kirshenbaum

Yan Li

Steven Theodore Sprouse

Jun Wan

Mohan Dunga

Daniel Joseph Linnen

Niles Yang

Changyuan Chen

Biswajit Ray

Dongxiang Liao

Pitamber Shukla

Xinmiao Zhang

Nan Lu

Ashish Ghai

Joanna Lai

Avinash Rajagiri

Srikar Peesari

Gautham Reddy

Chris Yip

Zelei Guo

Tienchien Kuo

Bin Wu

Abuzer Azo Dogan

Methods and apparatus for storing parity bits in an available over provisioning (OP) space to recover data lost from an entire memory block. For example, a data storage device may receive data from a host device, write the data to a block, and generate a corresponding block parity. The device may then determine a bit error rate (BER) of the block and an average programming duration to write the data written to the block, calculate a probability of the block becoming defective based on the BER and the average programming duration, and comparing the probability of the block to a set of probabilities respectively corresponding to a set of worst-performing blocks in a NVM. Thereafter, the device may write the block parity to an available over provisioning (OP) space in the NVM responsive to the probability of the block being greater than any probability in the set of probabilities.

Using over provisioning space for selectively storing block parity

Techniques are described for performing a read scan process on a non-volatile memory system in order to determine memory blocks that may have a high bit error rate, where if such blocks are found they can be refreshed. Rather than work through the blocks of a memory system sequentially based on the physical block addresses, the memory system maintains a measure of data quality, such as an estimated or average bit error rate, for multi-block groups. For example, the groups can correspond to regions of memory die in the system. The groups are ranked by their data quality, with the groups being scanned in order of the data quality. The blocks within a group can also be ranked, based on factors such as the program/erase count.

Enhancing the effectiveness of read scan performance and reliability for non-volatile memory

Disclosed are systems and methods for providing pre-program read to counter wordline failures. A method includes performing a read operation on a first portion of a flash memory in response to an erase operation on a second portion of the flash memory, wherein the first portion comprises a plurality of logical wordlines corresponding to a plurality of physical wordlines of the second portion. The method also includes counting, for each of the plurality of logical wordlines, a number of memory cells exceeding a threshold error voltage and marking defective physical wordlines in a bitmap. The method also includes performing a write operation into a third portion of the flash memory that includes at least one physical wordline marked as defective in the error bitmap, wherein a predetermined data pattern is written to a lower page of the at least one physical wordline.

Pre-program read to counter wordline failures

Over a period of operation, non-volatile memory can develop a residual resistance that is impractical to remove. For example, in a NAND string of memory cells, trapped charge may build up in a region between the bit lines and drain side select gates, so that even when all the devices of a NAND string are in an 'on' state, the NAND string will not conduct. This effect will skew both hard bit data determinations, indicating the data state of a selected memory cell, and soft bit data determinations which may correlate to the reliability of the hard bit data. Techniques are described to factor in such excessive residual resistance when determining the soft bit data.

Read verify for improved soft bit information for non-volatile memories with residual resistance

On a non-volatile memory circuit, peripheral circuitry generates programming voltages based on parameter values. If parameter values are incorrectly translated into programming voltages, data may be over-programmed, resulting in high bit error rates (BERs). The memory system can monitor the error rates using memory cell voltage distributions for different portions of the memory and look for signatures of such incorrect implementation. For example, by monitoring the BER along word lines that are most prone to error due to incorrectly implemented programming parameters, the memory system can determine if the programming parameters for the corresponding portion of a memory device indicate such anomalous behavior. If such a signature is found, the memory system checks to see whether the programming parameters should be adjusted, such as by comparing the programming parameters used on one die to programming parameters used on another die of the memory system, and adjust the programming parameters accordingly.

Parameter tracking for non-volatile memory to avoid over-programming

Apparatuses, systems, methods, and computer program products for dynamically determining boundary word line voltage shift are presented. An apparatus includes an array of non-volatile memory cells and a controller. A controller includes a trigger detection component that is configured to detect a trigger condition associated with a last programmed word line of a partially programmed erase block of an array of non-volatile memory cells. A controller includes a voltage component that is configured to determine a read voltage threshold for a last programmed word line of a partially programmed erase block in response to a trigger condition. A controller includes a voltage shift component that is configured to calculate, dynamically, a read voltage threshold shift for a last programmed word line based on a determined read voltage threshold for the last programmed word line and a baseline read voltage threshold.

Boundary word line voltage shift

A device includes a memory device and a controller. The controller is coupled to the memory device. The controller is configured to, in response to receiving a request to perform a memory access at the memory device, determine that the memory device has a characteristic indicative of a temperature crossing. The controller is also configured to, in response to determining that the memory device has the characteristic indicative of the temperature crossing, determine that the memory device satisfies an availability criterion. The controller is further configured to, in response to determining that the memory device satisfies the availability criterion, increase a temperature of the memory device by performing memory operations on the memory device until detecting a condition related to the temperature.

Memory die temperature adjustment based on a power condition

Apparatuses, systems, methods, and computer program products are disclosed for performing read mode tuning. An apparatus includes an error rate storage circuit that determines error rate information. An apparatus includes a mode selection circuit that determines a read mode of a plurality of read modes for reading a set of memory cells based on error rate information. The plurality of read modes may include a fast read mode and a normal read mode. An apparatus includes a read circuit that performs a read on a set of memory cells based on a read mode.

Read mode tuning

Apparatuses, systems, methods, and computer program products are disclosed for performing a group read refresh. An apparatus includes a plurality of memory groups. An apparatus includes an operation circuit that performs an operation on a selected memory group of a plurality of memory groups. An apparatus includes a remediation circuit that performs a countermeasure operation on an unselected memory group of a plurality of memory groups in response to an operation on a selected memory group.

Group read refresh

A storage system and method for reducing XOR recovery time are provided. In one embodiment, a storage system is provides comprising a memory and a controller. The controller is configured to generate a first exclusive-or (XOR) parity for pages of data written to the memory; after the first XOR parity has been generated, determine that there is at least one page of invalid data in the pages of data written to the memory; and generate a second XOR parity for the pages of data that excludes the at least one page of invalid data, wherein the second XOR parity is generated by performing an XOR operation using the first XOR parity and the at least one page of invalid data as inputs. Other embodiments are possible, and each of the embodiments can be used alone or together in combination.

Storage system and method for reducing XOR recovery time by excluding invalid data from XOR parity

Certain apparatuses, systems, methods, and computer program products are used for multi-plane memory management. An apparatus includes a failure detection circuit that detects a failure of a storage element during an operation. An apparatus includes a test circuit that performs a test on a storage element. An apparatus includes a recycle circuit that enables a portion of a storage element for use in operations in response to the portion of the storage element passing a test.

Multi-plane memory management

Systems and methods are described for compacting operating parameter sets in a data storage device. Data storage device may be configured to maintain multiple operating parameter sets, each of which stores various parameters for interacting with different memory elements within the device. The data storage device may further be limited in the total number of operating parameter sets that can be maintained in the device at any given time. Thus, the data storage device may be required at various times to combine two or more operating parameter sets, to enable creation of a new operating parameter set. Because each operating parameter set can contain a number of parameters, identification of similar sets for combination can be computationally intensive. To identify similar sets in an efficient manner, a device as disclosed herein is enabled to reduce a dimensionality of each set, and locate similar sets under that reduced dimensionality.

Compacting operating parameter groups in solid state memory devices

Systems and methods are described for generating location-based read voltage offsets in a data storage device. Optimal read voltage thresholds vary across memory elements of a device. However, data storage devices are often limited in the number of read voltage thresholds that can be maintained in the device. Thus, it may not be possible to maintain optimal read voltage parameters for each memory element within a device. The systems and methods described herein provide for increased accuracy of read voltage thresholds when applied to memory elements within a specific location in a device, by enabling the use of location-based read voltage offsets, depending on a relative location of the memory element being read from. The read voltage offsets can be determined based on application of a neural network to data regarding optimal read voltage thresholds determined from at least a sample of memory elements in a device.

Operating parameter offsets in solid state memory devices

A memory device and associated techniques avoid reading memory cells immediately after programming when uncorrectable errors may be present. In one aspect, data is copied from one block to another block and a timer is started after the copying is completed. If a read command is received before the timer has expired, the read operation proceeds by reading the one block. If the read command is received after the timer has expired, the read operation proceeds by reading the another block. This approach is particular suitable when data is copied from single-level cell (SLC) blocks to multi-level cell (MLC) blocks in a folding operation. The duration of the timer can be increased at lower temperatures.

Delayed data release after programming to reduce read errors in memory

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Santa Clara, CA, United States of America

Philip David Reusswig